Cellulose ether coating compositions and methods

ABSTRACT

The present disclosure is directed to cellulose ether compositions for film-forming coating applications. A coating composition is provided which contains an aqueous solution of either a very low viscosity cellulose ether or a low-hydroxypropyl cellulose ether, the coating composition having low color. The low viscosity of the cellulose ether component enables the coating composition to contain a high concentration of cellulose ether. Provision of these high concentration cellulose ether coating solutions improves production efficiency by reducing the time required to coat a substrate.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. patent application Ser. No.60/986,731, filed on Nov. 9, 2007, the entire content of which isincorporated by reference herein.

BACKGROUND

The present disclosure relates to cellulose ether coating compositions,and coated compositions produced therewith.

Cellulose ethers are commonly used as a film coating material ontablets, as a food additive, and in pharmaceutical capsules. Lowmolecular weight cellulose ethers oftentimes exhibit yellowing ordiscoloration. It is known that as the molecular weight of the celluloseether decreases, the degree of discoloration increases. Using celluloseethers of higher molecular weight improves the color, however, highermolecular weight cellulose ethers are difficult to use in spray coatingoperations.

It would be desirable to develop low molecular weight cellulose ethercoating compositions that are readily applied to a substrate and providea coating acceptable for appearance-sensitive applications.

SUMMARY

The present disclosure is directed to cellulose ether compositions forcoated applications and coated products made using these compositions.The present disclosure is also directed to methods for producing coatedcompositions. In an embodiment, a composition is provided. Thecomposition may be a coating composition. The composition includes aplasticizer and an aqueous solution of a very low viscosity celluloseether. The very low viscosity cellulose ether is present in an amount ofat least 10% by weight of the composition. The very low viscositycellulose either has a viscosity from 1.2 cP to less than 2 cP whenmeasured as a 2% by weight aqueous solution concentration at 20° C. Inan embodiment, the very low viscosity cellulose ether may also have lowcolor and have an APHA value from 1 to 100. In a further embodiment, thevery low viscosity cellulose ether is also a very low color celluloseether having an APHA value from 1 to 20.

In an embodiment, the composition may include one or more additionalcomponents from the following: a solids-loading enhancer, a secondcellulose ether, a surfactant, a lubricant, a polishing agent, apigment, an anti-tack agent, a glidant, an opacifier, and combinationsthereof.

The coating composition has a total solids content from at least 10% byweight to about 40% by weight. The viscosity of the composition is 100cP to 1000 cP, or from 100 cP to 500 cP (Brookfield viscosity).

The composition may be used to make a coated composition. In anembodiment, a coated composition is provided. The coated compositionincludes a substrate and a coating on the substrate. The coatingcontains the plasticizer and the very low viscosity cellulose ether. Thevery low viscosity cellulose ether is present in the coating in anamount of at least 10% by weight of the coating.

The coating may contain one or more of the following additionalcomponents: a surfactant, a coloring agent, a second cellulose ether, asolids-loading enhancer, a lubricant, a polishing agent, a pigment, ananti-tack agent, a glidant, an opacifier, and any combination of theseadditional components.

The present disclosure provides another composition. This compositionmay be a coating composition. In an embodiment, this compositionincludes an aqueous solution of a low-hydroxypropyl cellulose ether. Thelow-hydroxypropyl cellulose ether is present in the composition in anamount of at least 10% by weight of the composition. Thelow-hydroxypropyl cellulose ether has a viscosity less than 3 cP whenmeasured as a 2% by weight aqueous solution at 20° C. In an embodiment,the low-hydroxypropyl cellulose ether is a very low color celluloseether having an APHA value from 1 to 20. The composition may alsoinclude a coloring agent and/or a plasticizer.

In an embodiment, the composition may include one or more of thefollowing additional components: a solids-loading enhancer, a secondcellulose ether, a surfactant, a lubricant, a polishing agent, apigment, an anti-tack agent, a glidant, an opacifier and any combinationof these additional components. The composition has a total solidscontent from 10% by weight to about 40% by weight.

The composition may be used to produce a coated composition. In anembodiment, another coated composition is provided. The coatedcomposition includes a substrate and a coating on the substrate. Thecoating contains at least 10% by weight of the low-hydroxypropylcellulose ether. In an embodiment, the coating is a single layer film ofthe low-hydroxypropyl cellulose ether.

The substrate may include one or more surfaces and one or more edges. Inan embodiment, the coating covers a surface and an edge of thesubstrate. In a further embodiment, the coating is a uniform coating.Thus, the coating may have a constant thickness along and on the surfaceas well as around and on the edge.

In an embodiment, the coating may include one or more of the followingadditional components: a plasticizer, a solids-loading enhancer, asecond cellulose ether, a surfactant, a lubricant, a polishing agent, apigment, an anti-tack agent, a glidant, an opacifier, and anycombination thereof.

In an embodiment, a method for preventing edging is provided. The methodincludes spraying an aqueous solution on a substrate. The aqueoussolution may contain at least 10% by weight of a low-hydroxypropylcellulose ether. The substrate has a surface and an edge. The methodincludes forming a coating on the surface and the edge. In anembodiment, the aqueous solution contains a plasticizer. The coating maybe a film of the plasticizer and the low-hydroxypropyl cellulose ether.In an embodiment, the method includes forming a uniform coating on thesurface and the edge.

An advantage of the present disclosure is the provision of an improvedcomposition for coating substrates.

An advantage of the present disclosure is the provision of an improvedcoated composition.

An advantage of the present disclosure is the provision of coatingcompositions with high concentrations of cellulose ether, thecompositions having a color acceptable for appearance-sensitiveapplications.

An advantage of the present disclosure is the provision of celluloseether-based coating compositions with high concentrations of totalsolids.

An advantage of the present disclosure is a reduction in the timerequired to coat a substrate with a cellulose ether.

An advantage of the present disclosure is the reduction in the amount ofcoating composition required to form a film coating on a substrate.

An advantage of the present disclosure is the reduction and/orelimination of edging during a spray coating operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a coated composition in accordance withthe present disclosure.

FIG. 2 is a sectional view of a coating composition exhibiting edging.

FIG. 3 is a graph comparing dissolution rates for uncoated tablets andcoated compositions in accordance with the present disclosure.

DETAILED DESCRIPTION

Any numerical range recited herein, includes all values from the lowervalue and the upper value, in increments of one unit, provided thatthere is a separation of at least two units between any lower value andany higher value. As an example, if it is stated that a compositional,physical or other property, such as, for example, molecular weight, meltindex, etc., is from 100 to 1,000, it is intended that all individualvalues, such as 100, 101, 102, etc., and sub ranges, such as 100 to 144,155 to 170, 197 to 200, etc., are expressly enumerated in thisspecification. For ranges containing values which are less than one, orcontaining fractional numbers greater than one (e.g., 1.1, 1.5, etc.),one unit is considered to be 0.0001, 0.001, 0.01 or 0.1, as appropriate.For ranges containing single digit numbers less than ten (e.g., 1 to 5),one unit is typically considered to be 0.1. These are only examples ofwhat is specifically intended, and all possible combinations ofnumerical values between the lowest value and the highest valueenumerated, are to be considered to be expressly stated in thisapplication. Numerical ranges have been recited, as discussed herein, inreference to density, weight percent of component, tan delta, molecularweights and other properties.

The term “composition,” as used herein, includes a mixture of materialswhich comprise the composition.

The terms “blend” or “polymer blend,” as used herein, mean a compositionof two or more polymers. Such a blend may or may not be miscible. Such ablend may or may not be phase separated. Such a blend may or may notcontain one or more domain configurations, as determined fromtransmission electron microscopy.

In an embodiment, a composition is provided. The composition may be acoating composition. The composition includes an aqueous solution of avery low viscosity cellulose ether and a plasticizer. The very lowviscosity cellulose ether serves as a film-forming agent and is presentin an amount of at least 10% by weight of the composition, or at least20% by weight, or from 10% to 40% (or any value or subrangetherebetween), or from 20% to 30%, or from 20% to 27%, or from 20% to24% by weight of the composition. As used herein, a “very low viscosity”(VLV) cellulose ether is a cellulose ether having a molecular weightsuch that a 2% by weight aqueous solution of it at 20° C. has aviscosity of from 1.2 centipoise (cP) to less than 2 cP (or any value orsubrange therebetween). Unless stated otherwise, the viscosity valuesset forth herein are determined according to ASTM D1347 (methylcellulose) and/or ASTM D2363 (hydroxypropylmethylcellulose) measured asa 2% by weight cellulose ether aqueous solution at 20° C.

A “cellulose ether,” as used herein, is an ether-linked derivative,either partial or complete, of cellulose. Cellulose ether is producedfrom cellulose pulp, typically obtained from wood or cotton. Thecellulose pulp is converted into alkaline cellulose by alkalizing thecellulose pulp with an alkali hydroxide, and then etherifying thealkalized cellulose in a dry, gas-phase or slurry process with one ormore etherifying agents The molecular weight of these cellulose etherscan then be reduced by depolymerizing the cellulose ether with an acid,such as hydrogen chloride, and optionally neutralizing the depolymerizedcellulose ether with a basic compound, such as anhydrous sodiumbicarbonate. Alternatively, the cellulose ether may be depolymerized byway of acid catalyzed degradation, oxidative degradation, degradation byhigh-energy radiation, and degradation by way of microorganisms orenzymes.

The cellulose ether may be a “water soluble” cellulose ether or a “waterinsoluble” cellulose ether. A “water-soluble” cellulose ether is acellulose ether that prior to the partial depolymerization has asolubility in water of at least 2 grams in 100 grams of distilled waterat 25° C. and 1 atmosphere. Nonlimiting examples of water solublecellulose ethers include carboxy-C₁-C₃-alkyl celluloses, such ascarboxymethyl celluloses; carboxy-C₁-C₃-alkyl hydroxy-C₁-C₃-alkylcelluloses, such as carboxymethyl hydroxyethyl celluloses; C₁-C₃-alkylcelluloses, such as methylcelluloses; C₁-C₃-alkyl hydroxy-C₁₋₃-alkylcelluloses, such as hydroxyethyl methylcelluloses, hydroxypropylmethylcelluloses or ethyl hydroxyethyl celluloses; hydroxy-C₁₋₃-alkylcelluloses, such as hydroxyethyl celluloses or hydroxypropyl celluloses;mixed hydroxy-C₁-C₃-alkyl celluloses, such as hydroxyethyl hydroxypropylcelluloses, mixed C₁-C₃-alkyl celluloses, such as methyl ethylcelluloses, or alkoxy hydroxyethyl hydroxypropyl celluloses, the alkoxygroup being straight-chain or branched and containing 2 to 8 carbonatoms.

The cellulose ether may be a water-insoluble cellulose ether. A“water-insoluble” cellulose ether is a cellulose ether that prior to thepartial depolymerization has a solubility in water of less than 2 grams,or less than 1 gram in 100 grams of distilled water at 25° C. and 1atmosphere. A nonlimiting example of a water-insoluble cellulose etheris ethylcellulose.

In an embodiment, the cellulose ether is methylcellulose, hydroxyethylcellulose, hydroxypropyl cellulose, hydroxyethylmethyl cellulose,hydroxypropylmethyl cellulose, hydroxybutylmethyl cellulose,ethylhydroxyethyl cellulose, carboxymethyl cellulose, and carboxymethylhydroxyethylcellulose.

In a further embodiment, the cellulose ether ishydroxypropylmethylcellulose (HPMC) or methylcellulose (MC). HPMC and/orMC are available under the METHOCEL trademark from The Dow ChemicalCompany, Midland, Mich. Nonlimiting examples of suitable HPMC and MC areset forth in Table 1 below.

TABLE 1 METHOCEL ™ Products Methoxyl Hydroxypropyl Viscosity of 2%METHOCEL ™ Product Chemical Type Content, % Content, % solution inwater, cps METHOCEL ™ A15 Methylcellulose, 27.5-31.5 0 12-18 Premium LVUSP METHOCEL ™ A4C Methylcellulose, 300-560 Premium USP METHOCEL ™ A15CMethylcellulose, 1125-2100 Premium USP METHOCEL ™ A4M Methylcellulose,3000-5600 Premium USP METHOCEL ™ E3 Premium Hypromellose 28-30 7-122.4-3.6 LV 2910 METHOCEL ™ E5 Premium Hypromellose 28-30 7-12 4-6 LV2910 METHOCEL ™ E6 Premium Hypromellose 28-30 7-12 5-7 LV 2910METHOCEL ™ E15 Hypromellose 28-30 7-12 12-18 Premium LV 2910 METHOCEL ™E50 Hypromellose 28-30 7-12 40-60 Premium LV 2910 METHOCEL ™ E4MHypromellose 28-30 7-12 3000-5600 Premium 2910 METHOCEL ™ E10MHypromellose 28-30 7-12   7500-14,000 Premium CR 2910 METHOCEL ™ F50Hypromellose 27-30  4-7.5 40-60 Premium 2906 METHOCEL ™ F4M Hypromellose27-30  4-7.5 3000-5600 Premium 2906 METHOCEL ™ K3 Premium Hypromellose19-24 7-12 2.4-3.6 LV 2208 METHOCEL ™ K100 Hypromellose 19-24 7-12 80-120 Premium LV 2208 METHOCEL ™ K4M Hypromellose 19-24 7-123,000-5,600 Premium 2208 METHOCEL ™ K15M Hypromellose 19-24 7-1211,250-21,000 Premium 2208 METHOCEL ™ K100M Hypromellose 19-24 7-12 80,000-120,000 Premium 2208

The cellulose ether may be a high-hydroxypropyl cellulose ether or alow-hydroxypropyl cellulose ether. As used herein, a “high-hydroxypropylcellulose ether” is a hydroxypropylmethylcellulose having 28-30% byweight methoxyl groups and 7.0-12.0% by weight hydroxypropoxyl groups. Anonlimiting example of a high-hydroxypropyl cellulose ether isHypromellose 2910 available from The Dow Chemical Company, Midland,Mich. under the trademark METHOCEL E. A “low-hydroxypropyl celluloseether” is a hydroxypropylmethylcellulose having 27-30% by weightmethoxyl groups and 4.0-7.5% by weight hydroxypropxyl groups. Anonlimiting example of a low-hydroxypropyl cellulose ether isHypromellose 2906 available from The Dow Chemical Company, Midland,Mich. under the trademark METHOCEL F.

In an embodiment, the VLV cellulose ether has an American Public HealthAssociation (APHA) color value from 1 to 100 (or any value or subrangetherein) or from 1 to 50, or from 1 to 30, or from 1 to 20. The APHAvalue is determined in accordance with ASTM D-5386 (2% concentration inaqueous solution at ambient temperature). In a further embodiment, theVLV cellulose ether is a very low color cellulose ether. As used herein,a “very low color” (VLC) cellulose ether is a cellulose ether having anAPHA value from 1 to 20 (or any value or subrange therebetween). VLVcellulose ether and/or VLC cellulose ether may be produced as set forthin U.S. Patent Application Ser. No. 60/986,686 (Attorney Docket No.34995) filed on Nov. 9, 2007, the entire content of which isincorporated by reference herein.

In an embodiment, the composition includes a plasticizer. Theplasticizer present in the composition improves film performance of thecellulose ether in the aqueous solution. The plasticizer may be apolyethylene glycol, castor oil, dibutyl sebacate, diethyl phthalate,glycerol, polyethylene glycol methyl ether, triacetin, triethyl citrate,a phospholipid, lecithin, propylene glycol, and any combination thereof.In an embodiment, the plasticizer is present in an amount from 1% to 10%by weight (or any value or subrange therebetween), or from 1% to 5% byweight, or from 2% to 4% by weight of the composition. In a furtherembodiment, the plasticizer is a polyethylene glycol having a molecularweight from about 100 to about 1000 (or any value or subrangetherebetween), or a molecular weight of about 400.

In an embodiment, the composition includes a surfactant. The surfactantlowers the surface tension of the aqueous solution to promote dispersionof the VLV cellulose ether and/or the surfactant facilitates thespreading of the coating composition on the substrate. The surfactantmay be a polyoxylated sorbitol and fatty acid (i.e., sorbitanmonolaurate, sorbitan monopalmitate, sorbitan monostearate, or sorbitanmonooleate or polysorbate), sodium lauryl sulfate, docusate sodium,glyceryl monostearate, poloxamer, polyoxyethylene alkyl ether,polysorbate, sorbitan fatty acid ester, lecithin, and phospholipid. Thesurfactant is present in an amount from about 0.001 to 0.5% by weight(or any subrange or value therebetween), or from 0.001-0.1% by weight,or from 0.001 to 0.07% by weight of the composition.

In an embodiment, the composition includes a coloring agent. Thecoloring agent may be any FD & C lake, D & C lake, dye (water soluble orwater insoluble) approved for ingestion by the U.S. Federal DrugAdministration or similar governmental regulatory body. In anembodiment, the coloring agent is an aluminum-based lake. The coloringagent is present in an amount from 0.05% to 7% by weight (or any valueor subrange therebetween), or from 0.1% to 1.5% by weight, or from 0.45%to 0.75% by weight of the composition. The composition may include apigment. The pigment may be present in an amount from 0.5% to 7% byweight (or any value or subrange therebetween, or from 0.1% to 1.5% byweight or from 0.4% to 0.8% by weight of the composition.

In an embodiment, the composition includes a second cellulose ether. Thesecond cellulose ether serves as a supplemental film-forming agent. Thesecond cellulose ether may be a high viscosity cellulose ether, a lowviscosity cellulose ether, or a combination thereof. A “high viscosity”cellulose ether is a cellulose ether having a molecular weight such thata 2% by weight aqueous solution of it at 20° C. has a viscosity greaterthan 400 cP, or from 400 cP to 100,000 cP. Alternatively, the secondcellulose ether may be a low viscosity cellulose ether. A “lowviscosity” cellulose ether is a cellulose ether having a molecularweight such that a 2% by weight aqueous solution of it at 20° C. has aviscosity of 2 centipoise (cP) to 400 cP. In a further embodiment, thesecond cellulose ether is a low viscosity HPMC present in an amount from0.01% to 1.5% by weight (or any value or subrange therebetween), orabout 1% by weight of the composition. It has unexpectedly andsurprisingly been found that provision of the second cellulose etheradvantageously prevents edging when the composition is sprayed onto asubstrate.

In an embodiment, the composition may include one or more of thefollowing components: a solids-loading enhancer, a second surfactant, alubricant/polishing agent, a pigment, an anti-tack agent, a glidant, anopacifier, and any combination thereof. Nonlimiting examples of suitablesolids-loading enhancers include high molecular weight water solublepoly(ethylene oxide) polymers (POLYOX™), acacia, and sugars (such aslactose). The lubricant/polishing agent may be a wax such as carnaubawax or beeswax. The pigment may be titanium dioxide. The anti-tack agentand/or the glidant may be talc, collidal silicon dioxide, glycerylmonostearate, and combinations thereof. The opacifier may be calciumcarbonate.

The composition may have a total solids content from at least 10% toabout 40% by weight (or any value or subrange therebetween), or from 20%to 40%, or from 23% to 35% by weight, or from 24% to 29% by weight ofthe composition. The viscosity of the composition may be from 100 cP to1000 cP (or any value or subrange therebetween), or from 100 cP to 500cP (Brookfield viscosity).

The composition may be applied to a substrate to form a coatedcomposition. Coating devices such as a fluidized bed coating device, apan coating device, and/or a flow-through rotational drum type coatingdevice may be used to apply, spray, or atomize the composition onto theexterior of a substrate. Thus, the present disclosure provides a coatedcomposition. In an embodiment, the coated composition includes asubstrate and a coating on the substrate. The coating contains the VLVcellulose ether and the plasticizer. The VLV cellulose ether is presentan amount of at least 10%, or greater than 20%, or at least 10% to 40%by weight of the coating. In an embodiment, the coating includes asurfactant and a coloring agent.

As used herein, a “substrate” is an object capable of being partially orfully covered with cellulose ether. Nonlimiting examples of suitablesubstrates include tablets for oral ingestion, food products,pharmaceutical products (pharmaceutical tablets and capsules),medicaments, drugs, seeds, animal feed, granules, beads, powder, trochesand fertilizer. The substrate may also be an encapsulate such as aparticulate material, the particulate material being encapsulated(micro- or macro-encapsulation) by the coating.

The coating may be located on a portion of the substrate. In anotherembodiment, the coating surrounds the entire substrate and encapsulatesthe substrate. Consequently, the VLV cellulose ether forms a film on (i)a portion of the substrate or (ii) around the entire substrate. In anembodiment, the dried coating may be 1% to 20% by weight (or any valueor subrange therebetween) of the substrate.

In an embodiment, the coating includes a second cellulose ether. Thesecond cellulose ether may be any cellulose ether as previouslydescribed herein. In a further embodiment, the coating contains one ormore of the following components: a solids-loading enhancer, a secondsurfactant, a lubricant/polishing agent, a pigment, an anti-tack agent,a glidant, an opacifier, and any combination thereof. The presence ofeach of these components in the coating may correspond to the amount ofeach compound that is present in the foregoing coating composition.

The composition may comprise two or more embodiments disclosed herein.

The present disclosure provides another composition. This compositionmay be a coating composition. In an embodiment, the composition includesan aqueous solution of a low-hydroxypropyl cellulose ether. The solutioncontains at least 10% by weight, or greater than 20% by weight, or from10% to 30% by weight (or any value or subrange therebetween), or from14% to 23% by weight, or from 16% to 21% by weight of thelow-hydroxypropyl cellulose ether. The low-hydroxypropyl cellulose etherserves as a film-forming agent. In an embodiment, the composition mayinclude a plasticizer and/or may include a coloring agent.

In an embodiment, the low-hydroxypropyl cellulose ether has a viscosityless than 3 cP when measured as a 2% by weight aqueous solution at 20°C. For example, the low-hydroxypropyl cellulose ether has a viscosityfrom 1.2 cP to 3 cP (or any value or subrange therebetween), or from2.61 cP to 2.66 cP. In a further embodiment, the low-hydroxypropylcellulose ether is a VLC cellulose ether having an APHA value from 1-20(or any value or subrange therebetween), or from 15 to 16.5. Thelow-hydroxypropyl cellulose ether with a viscosity less than 3 cP (andvery low color) may be produced as set forth in U.S. Patent ApplicationSer. No. 60/986,686 (Attorney Docket No. 34995) filed on Nov. 9, 2007,the entire content of which is incorporated by reference herein.

The plasticizer may be any plasticizer as previously disclosed herein.The plasticizer may be present in an amount from 1% to 10% by weight (orany value or subrange therebetween), 1% to 3.3% by weight, or 1.6% to2.2% by weight of the composition. In an embodiment, the plasticizer isa polyethylene glycol.

The coloring agent may be any coloring agent as previously disclosedherein. The coloring agent may be present in an amount from 0.5% to 7%by weight (or any value or subrange therebetween, or from 0.1% to 1.5%by weight or from 0.4% to 0.8% by weight of the composition. In anembodiment, the coloring agent may be an aluminum lake pigment and/or awater soluble dye. The composition may include a pigment. The pigmentmay be present in an amount from 0.5% to 7% by weight (or any value orsubrange therebetween, or from 0.1% to 1.5% by weight or from 0.4% to0.8% by weight of the composition.

In an embodiment, the composition may include one or more of thefollowing components: a surfactant, second cellulose ether, asolids-loading enhancer, a lubricant/polishing agent, an anti-tackagent, a glidant, an opacifier and combinations thereof. The compositionhas a total solids content from 10% by weight to about 40% by weight (orany value or subrange therebetween), or from 15% to 28% by weight, orfrom 18% to 25% by weight of the composition.

This composition may be applied to a substrate to form a coatedcomposition as previously disclosed herein. Thus, the present disclosureprovides another coated composition. In an embodiment, a coatedcomposition 10 includes a substrate 12 and a coating 14 on the substrateas shown in FIG. 1. The coating 14 contains at least 10% by weight, orgreater than 20% by weight, or from 10% to 40% by weight (or any valueor subrange therebetween), or from 14% to 23% by weight, or from 16% to21% by weight of the low-hydroxypropyl cellulose ether. Thelow-hydroxypropyl cellulose ether present in the coating 14 may have aviscosity less than 3 cP and/or may be a VLC cellulose ether asdiscussed above.

The coating may be located on a portion of the substrate. Alternatively,the coating 14 surrounds the entire substrate 12 and encapsulates thesubstrate as shown in FIG. 1. Consequently, the low-hydroxypropylcellulose ether forms a film on (i) a portion of the substrate or (ii)around the entire substrate.

In an embodiment, the coating may include one or more of the followingcomponents: a plasticizer, a coloring agent, a second cellulose ether, asurfactant, a solids-loading enhancer, a pigment, a lubricant/polishingagent, an anti-tack agent, a glidant, an opacifier and combinationsthereof. The amount for each of these components may be the same as (orgreater than) the respective amount for each component in thecomposition as discussed above.

In an embodiment, the substrate 12 has one or more surfaces 16 a, 16 b,16 c, 16 d and one or more edges 18 a, 18 b, 18 c, and 18 d. The coating14 covers at least one surface and at least one edge. In a furtherembodiment, the coating 14 covers all the surfaces 16 a-16 d and all theedges 18 a-18 d as shown in FIG. 1.

In an embodiment, the coating containing the low-hydroxypropyl celluloseether may be used to prevent edging. As used herein, “edging” is thephenomenon whereby the edges of a substrate are uncoated and thesurfaces are coated during a spray coating process. Edging is typicallyobserved during the spray coating of tablets, for example. FIG. 2 showsa coated composition 50 exhibiting edging. The coating 54 coverssurfaces 56 a, 56 b, 56 c, and 56 d of the substrate 52. However, one ormore edges 58 a, 58 b, 58 c, and 58 d are not covered by the coating 54to the same extent as surfaces 56 a-d are covered.

Not wishing to be bound by any particular theory, it is believed thatthe high concentration of the low-hydroxypropyl cellulose ether in thecoating composition and the low amount of hydroxypropyl groups presentin low-hydroxypropyl cellulose ether contribute to promote coatingadherence to the substrate and film formation around the substrate edgesduring spray application. It has surprisingly and unexpectedly beenfound that coating solutions containing high concentrations (i.e., atleast 10% by weight) of the low-hydroxypropyl cellulose ether reduce,even eliminate, edging during a spray coating process. Consequently, inan embodiment, the low-hydroxypropyl cellulose ether solution permitscoverage of the entire substrate 12 with a single layer of the coating14 (FIG. 1).

In an embodiment, the coating 14 is a uniform coating along the surfacesand the edges of the substrate 12. As used herein, “uniform” is aconstant thickness along the extent of the coating. FIG. 1 shows athickness 20 for the coating 14. The thickness 20 is the same orconstant at all points around the circumference of the coatedcomposition 10. In other words, the thickness 20 of the coating 14 isthe same, or substantially the same, at the edges 18 a-18 d as it isalong the surfaces 16 a-16 d.

The coated composition may comprise two or more embodiments disclosedherein.

In an embodiment, a method for preventing edging is provided. The methodincludes spraying an aqueous solution containing a low-hydroxypropylcellulose ether onto a substrate. The solution contains at least 10% byweight or greater than 20% by weight, or from 10% to 40% by weight (orany value or subrange therebetween), or from 14% to 23% by weight, orfrom 16% to 21% by weight of the low-hydroxypropyl cellulose ether. Thesubstrate has a surface and an edge. The method includes forming acoating of the low-hydroxypropyl cellulose ether on the surface and onthe edge. In an embodiment, the solution may include a plasticizer. In afurther embodiment, the method includes forming a uniform coating on thesurface and on the edge.

Provision of the VLV cellulose ether and/or the low-hydroxypropylcellulose ether in the present coating compositions carry severaladvantages. The ability to spray the VLV celluloseether/low-hydroxypropyl cellulose ether at high concentration in aqueousenvironments render the coating compositions very useful as a tastemasking agent and as a flavor fixative in oral solid dosage forms,liquid suspensions, feed, veterinary applications and nutritionalsupplements. This also improves the visual attractiveness of theresultant coated composition by providing a smooth (non-stippled)surface, and uniform coating without edging. The VLV cellulose etherand/or the low-hydroxypropyl cellulose ether are also very useful forencapsulation techniques for producing oral solid dosage forms,veterinary and agricultural applications, food, feed, nutritionalsupplements and cosmetics.

The present disclosure provides coating compositions with significantlyhigher dissolved cellulose ether than conventional cellulose ethercoating compositions. High concentrations of dissolved VLV celluloseether and/or low-hydroxypropyl cellulose ether do not impair the abilityof the film-coating formulations containing these compositions to beatomized or uniformly coat a substrate. Because significantly higherfilm-forming polymer concentrations can be dissolved, coating times canbe significantly reduced beyond what is currently attainable. Inaddition, the present film-forming agents—such as the VLV celluloseether and the low-hydroxypropyl cellulose ether, for example—alsoexhibit VLC properties. This is particularly surprising for thelow-hydroxypropyl cellulose ether. Conventional low-hydroxypropylcellulose ether grades typically form significantly dark aqueoussolutions. Conversely, the applicants have surprisingly discovered amethod by which to apply film-coatings using highly concentratedfilm-coating solutions which contain low-hydroxypropyl cellulose etherwhile avoiding the unacceptable formation of dark-color which occurswith conventional low-hydroxypropyl cellulose ether film-coatingsolutions. Accordingly, significant time savings can be reaped whilesimultaneously producing high quality film-coated substrates with use ofthe compositions disclosed herein.

Concentrations of dissolved film-forming polymer, namely the VLVcellulose ether and the low-hydroxypropyl cellulose ether, aresignificantly higher than attainable with current conventional celluloseether grades (without adversely affecting atomization, coat uniformityor solution color). The total solids content in the coating compositionsdisclosed herein may be in excess of 10% by weight depending upon thelevels and types of additional excipients used (pigments, plasticizers,surfactants, etc.). This is advantageous as the present coatingcompositions provide high total solids-loading, yet the present coatingcompositions have a viscosity amenable to atomization and uniformfilm-coating application. Because significantly higher film-formingpolymer concentrations can be achieved, coating times can besignificantly reduced beyond what is currently attainable. In addition,production of dull film-coatings is avoided because the VLV celluloseether and the low-hydroxypropyl cellulose ether each exhibit VLCproperties. The VLV cellulose ether and the low-hydroxypropyl celluloseether are produced in such a way that the production of colorimetricby-products is avoided. Consequently, colorimetric by-products, whichimpart dark solution color commonly found in conventional celluloseether film-coating solutions are advantageously absent in the presentVLV cellulose ether and low-hydroxypropyl cellulose ether.

By way of example and not limitation, examples of the present disclosurewill now be given.

EXAMPLES Example 1 VLV Cellulose Ether Coating Composition

2% Viscosity, cP (ASTM Component D2363) Amount (% wt) Component A may beone or more of the following cellulose ether products: E1.8VLV 1.8 20-30E1.9VLV 1.9 E2.1VLV 2.1 E2.2VLV 2.2 Component B: polyethylene glycol 1-10 (MW = 400, CARBOWAX ™ SENTRY ™ 400, CAS No. 25322-68-3, The DowChemical Company). Component C: sodium lauryl sulfate 0.001-0.5  (MW =288.38, CAS No. 151-21-3, Sigma-Aldrich). Component D: aluminum lakepigment 0.05-7   (FD&C Yellow No. 5 HT Al Lake, product no. 5175,Colorcon, Inc.). Component E: water. qs Optional Additional ComponentsComponent F: METHOCEL E6PLV 6 film. Component G: SENTRY ™ POLYOX ™ WSRN-10 (CAS No. 25322-68-3, The Dow Chemical Company). Component H:lactose (CAS No 5989- 81-1). Component I: acacia (CAS No. 9000- 01-5).Component J: polysorbate 80 (CAS No. 9005-65-6). Component K:lubricating agent, carnauba wax (CAS No. 8015-86-9) or beeswax (CAS No.8012-89-3). Component L: pigment, titanium dioxde (CAS No. 13463-67-7)Component M: polishing agent, carnauba wax (CAS No. 8015-86-9) orbeeswax (CAS No. 8012-89-3). Component N: anti-tack agent glidant talc(CAS No. 14807-96-6), colloidal silicon dioxide (CAS No. 7631-86-9),glyceryl monostearate (CAS No. 31566- 31-1) Component O: opacifier,calcium carbonate (CAS No. 471-34-1)

To make the cellulose ether stock solutions, water is brought to a boilin a Sunbeam kettle (model no. K47AMD YE) containing an internal heatingcoil. After bringing the water to a rolling boil, the power supply tothe kettle is removed, and the water is then weighed into a beaker. Thewater is stirred using a StedFast™ Stirrer (model no. SL 600, FisherScientific) equipped with a marine propeller-type stirring shaft.Cellulose ether is slowly added to the stirring hot water until allcellulose ether is thoroughly dispersed. The dispersion is then allowedto equilibrate to room temperature under constant stirring. Uponreaching room temperature, cellulose ether is fully dissolved intosolution. Any water that has evaporated is replaced with fresh water.Each stock solution is then transferred to a jar, capped, and placed ona roller apparatus overnight for solution equilibration. Stock solutionsare stored at 15° C. until used. Prior to use, stock solutions areequilibrated to room temperature. Stock solution cellulose etherconcentrations of 15% (E6PLV) and 35% (w/w) (E2.1VLV) are used to makethe film-coating composition.

CARBOWAX™ SENTRY™ 400 is used as received.

To make the sodium lauryl sulfate (SLS) stock solution, water is weighedinto a beaker and stirred using a StedFast™ Stirrer equipped with amarine propeller-type stirring shaft. SLS is dissolved in the water tomake a 0.5% (w/w) stock solution. The stock solution is stored at roomtemperature.

To make the aluminum lake stock dispersions, water is weighed into abeaker of volume capacity at least twice that occupied by the finalaluminum lake stock dispersion. This is done to allow room for vigorousmixing during homogenization. The aluminum lake is weighed and added tothe water at a 5% (w/w) concentration. The dispersion is thenhomogenized with a rotor-stator homogenizer (Polyscience, model no.X-520) using the procedure listed in the table below.

The procedure is repeated 2-3 times to ensure sufficient dispersion andparticle size reduction of Aluminum lake.

Step Duration (seconds) Homogenize at 11,000 rpm 15 Homogenize at 15,000rpm 15 Homogenize at 19,000 rpm 15 Homogenize at 22,000 rpm 15Homogenize at 26,000 rpm 15 Cap jar and shake by hand 60 *rpm =revolutions per minute

The stock solutions, CARBOWAX™ SENTRY™ 400 and aluminum lake stockdispersion are blended together to achieve the desired concentration ofeach ingredient in the resulting film-coating formulation. Thecomponents are blended together using a StedFast™ Stirrer equipped witha marine propeller-type stirring shaft. The film-coating formulation isstirred continuously for at least 1 hour to ensure a homogeneousmixture.

The viscosity of the film-coating formulation is measured using aBrookfield Digital Viscometer (model no. DV 11, Brookfield EngineeringLaboratories, Inc.) equipped with an RV spindle set. Spindles 1 through7 are used as necessary depending on the viscosity of the film-coatingformulation. Spindle 1, the largest spindle, is used for the lowestviscosity samples. Spindle 7, the smallest spindle, is used for thehighest viscosity samples. The spindle rotation settings used are dialreadings of 0.5, 1, 2.5, 5, 10, 20, 50 and 100, with 0.5 being theslowest rotation speed and 100 the fastest. To prepare the instrument,the largest spindle necessary is estimated (depending upon visualobservation of the sample viscosity) and attached to the viscometer. Theviscometer is then calibrated for that particular spindle. The digitaldisplay is programmed to provide the viscosity data in cP units. Thedial is set to 0.5 and the spindle motor is turned on. The dial settingis gradually increased until the “low” indicator light turns off,indicating that the spindle speed is sufficient to obtain a validviscosity reading. Viscosity is recorded. Spindle setting is increasedand viscosity readings are recorded until the digital display reads“EEE”. This indicates that the spindle speed has become too fast toobtain a valid viscosity reading. The viscometer motor is turned offprior to removal of the spindle. Each time a different spindle is used,the viscometer was calibrated for that particular spindle and thedisplay programmed to provide the viscosity data in cP units. Ifpossible, one to three spindles are used to test the viscosity of eachstock solution or film-coating formulation.

Scored, oval placebo tablets (400 mg per tablet) are compressed using0.49″×0.27″ concaved tooling. The tablet formulation is listed in thetable below.

Scored, Oval Plaebo Tablet Formulation 69.85% DCL11 Pharmatose (lactose)29.65% Avicel PH 102 (microcrystalline cellulose) 0.50% Magnesiumstearate

Tablets are coated with the film-coating compositions using a HI-COATER(model LDCS, Vector Corporation) equipped with a 1.3-L baffled pan. Thespray nozzle is cleaned and calibrated using the “F3: Calibrate Guns”menu. The film-coating run parameters are programmed using the “F1:Manual Process” menu.

Prior to film-coating, a 400-600 g batch of tablets is introduced intothe pan, and the exhaust blower and process heat are initiated. The panis then intermittently operated (10 seconds on, 10 seconds off) in orderto equilibrate the tablets to the desired operating temperature. Exhausttemperature is used as the operating temperature set point, meaning thatthe heat is automatically adjusted to maintain the exhaust air at arelatively constant temperature. Once the desired exhaust temperature isattained, the pan is operated in continuous fashion, and thefilm-coating formulation is atomized via the nozzle onto the tumblingtablet bed. After the desired amount of film-coating formulation isintroduced onto the tumbling tablet bed, atomization is stopped, and thefilm-coated tablets are tumble-dried continuously at the same exhausttemperature for 30 minutes. After drying, the pan, process heat andexhaust blower are stopped in consecutive order.

The tablets are weighed before and after film-coating to determine thepercent weight gain. The film-coated tablets are visually inspected forbridging, coating of sharp curvatures, edging, and coat smoothness andhomogeneity.

VLV Cellulose Ether Coating Composition Ingredient Solids % (w/w)Quantity (g) E2.1VLV 20.0  75.03 (35% stock sol.) E6PLV 1.00  8.75 (15%stock sol.) Component B 3.30  4.33 Component C 0.001  0.26 (0.5% stocksol.) FD&C Yellow No. 5 HT Al Lake 0.50  13.17 (5% stock disp.) Water — 29.75 Total 24.8 131.3

VLV Cellulose Ether Coating Composition Viscosity (Brookfield Viscosity)Spindle Dial Setting Viscosity (cP) 3 50 460 3 100 440

VLV Cellulose Ether Coating Composition Run Parameters Pan Size 1.3 LPan Speed 20 rpm Exhaust Temperature Setpoint 25° C. Inlet Airflow Rate45 cfm Peristaltic Pump Rate 7 rpm Spray Rate 2.31 g/min NozzleAtomization Pressure 25 psi

VLV Cellulose Ether Coating Composition Run Results Coating Time 24.9min Tablet Weight Gain Target   3% Actual 3.48% Tablet Batch WeightStart 400.39 g Finish 414.31 g Tablet Appearance Aestheticallyacceptable. Uniform coating.

Upon visual inspection, the VLV cellulose ether-coated tablets areaesthetically acceptable and are uniformly coated. The tablets arecoated to a 3% weight gain target, with an actual weight gain of 3.48%.Inclusion of SLS into the film-coating formulation helps spread the VLVcellulose ether coating composition across the tablet surface. A lowerweight gain (3% vs. 4%) produces an equally aesthetic film-coating.

The experiment is repeated, except tablets containing naproxen sodiumare film-coated. Dissolution testing is conducted to ensure that thefilm-coating does not impede the release of naproxen sodium.

Dissolution testing (USP 29 Type 2 (Paddle) Method) is performed using aDistek Dissolution System 2100B (Crescent Scientific Pvt. Ltd.Goregaon-East, Mumbai, India) equipped with a Hewlett-Packard 8452ADiode Array Spectrophotometer (Hewlett-Packard Co. Palo Alto, Calif.,USA). Dissolution testing for each sample is conducted in replicates ofsix (n=6) using 900 mL deaerated, deionized water (deaerated using aDistek MD-1 De-Gasser) per standard vessel. Dissolution mediatemperature is equilibrated to 37.0±0.5° C. using a Distek TCS0200Bheater/circulator, and paddle speed is set at 50 rpm. Small cells (1.0mm) are used in the spectrophotometer. Dissolved naproxen sodium isquantified at ultraviolet wavelengths between 330 and 334 nm.

FIG. 3 shows that the VLV cellulose ether-coated tablets releasenaproxen sodium nearly identically to uncoated naproxen sodium tablets.

Example 2 VLV Cellulose Ether Coating Composition

VLV Cellulose Ether Coating Composition Ingredient Solids % (w/w) TargetQty. (g) E1.8 VLV 20.0 571.4 (35% stock sol.) Component F 1.0  50.0 (20%stock sot.) Component B 3.30  33.0 Component C 0.001   2.0 (0.5% stocksol.) FD&C Yellow No. 5 0.50 100.0 (5% stock disp.) HT Al Lake Water — 243.6 Total 24.8 1000.0

VLV Cellulose Ether Coating Composition Viscosity Spindle 1 Dial SettingViscosity (cP) 3 50 408 3 100 376

VLV Cellulose Ether Coating Composition Trial Parameters Pan Size 8.0 LPan Speed 20 rpm Exhaust Temperature Setpoint 35° C. Inlet Airflow Rate45 cfm Peristaltic Pump Rate 8 rpm Spray Rate 3.74 g/min NozzleAtomization Pressure 25 psi

VLV Cellulose Ether Coating Composition Results Coating Time 272.7 minTablet Weight Gain Target 4% Actual 3.35% Tablet Batch Weight Start 6000g Finish 6201 g Tablet Appearance Uniform coating, aestheticallyacceptable with glossy appearance. Observed spray drying in exhaust pan.

Example 3 Low-Hydroxypropyl Cellulose Ether Coating Composition

Component Color, APHA 2% Viscosity, cP Amount (% wt) Component A   10-30Low-hydroxypropyl cellulose 15 2.61 ether 2.61VLV Low-hydroxylpropylcellulose 16.5 2.66 ether 2.66VLV Component B: polyethylene glycol  1-10 (MW = 400, CARBOWAX ™ SENTRY ™ 400, CAS No. 25322-68-3, The DowChemical Company). Component C*: aluminum lake pigment 0.05-7 (FD&CYellow No. 5 HT Al Lake, product no. 5175, Colorcon, Inc.). ComponentD*: dye (FD&C Yellow 0.05-7 No. 5, product no. FD150, SpectrumChemical). Component E: water. qs * Component C or Component D is used,not necessarily both simultaneously. Optional Additional ComponentsComponent F: METHOCEL F4PLV. Component G: METHOCEL F50P. Component H:METHOCEL E6PLV. METHOCEL. Component I: sodium lauryl sulfate (MW =288.38, CAS No. 151-21-3, Sigma-Aldrich). Component J: SENTRY ™ POLYOX ™WSR N-10 (CAS No. 25322-68-3, The Dow Chemical Company). Component K:lactose (CAS No. 5989-81-1). Component L: acacia (CAS No. 9000-01-5).Component M: polysorbate 80. Component N: lubricant, carnauba wax (CASNo. 8015-86-9) or beeswax (CAS No. 8012-89-3). Component O: pigment,titanium dioxde (CAS No. 13463-67-7) Component P: polishing agent,carnauba wax (CAS No. 8015-86-9) or beeswax (CAS No. 8012-89-3).Component Q: anti-tack agent glidant talc (CAS No. 14807-96-6),colloidal silicon dioxide (CAS No. 7631-86-9), glyceryl monostearate(CAS No. 31566-31-1) Component R: opacifier, calcium carbonate (CAS No.471-34-1)

Low-hydroxypropyl cellulose ether F2.61VLV and low-hydroxypropylcellulose ether F2.66VLV are prepared using a depolymerization processcoupled with peroxide treatment to prevent polymer darkening duringdepolymerization. CARBOWAX™ SENTRY™ 400 (PEG, Dow Chemical) and FD&CYellow No. 5 (Spectrum Chemical, FDA lot no. AN3831) are used inconjunction with F2.61VLV and/or F2.66VLV to make low-hydroxypropylcellulose ether coating compositions. The materials, along with theircorresponding functions, are listed in the table below.

Ingredient Function Low-hydroxypropyl Cellulose Ether Film-Former PEG400 Plasticizer FD&C Yellow No. 5 Soluble Dye

Film Coating Liquid Preparation

All coating components are completely dissolved in the aqueous vehicle.Stock solutions are prepared as outlined below.

Preparation of Hypromellose Stock Solutions

To make each low-hydroxypropyl cellulose ether stock solution, water isbrought to a boil in a Sunbeam kettle (model no. K47AMD YE) containingan internal heating coil. After bringing the water to a rolling boil,the power supply to the kettle is removed, and the hot water is weighedinto a beaker (beaker tare weight recorded). The water is stirred usinga StedFast™ Stirrer (model no. SL 600, Fisher Scientific) equipped witha marine propeller-type stirring shaft. Low-hydroxypropyl celluloseether is slowly added to the stirring hot water until all of the powderis thoroughly dispersed. The dispersion is then allowed to equilibrateto room temperature under constant stirring. Upon reaching roomtemperature, the low-hydroxypropyl cellulose ether has fully dissolved.The amount of water that evaporates is determined since the weights ofthe beaker and ingredients are known. The water that evaporates isreplaced and mixed into the stock solution. The stock solution is thentransferred to a jar, capped, and placed on a roller apparatusovernight. The stock solution is stored at 15° C. until used. Prior touse, the stock solution is equilibrated to room temperature. Alow-hydroxypropyl cellulose ether stock solution concentration of 30%(w/w) is prepared.

Preparation of Dye Stock Solution

To make the FD&C Yellow No. 5 dye stock solution, water is weighed intoa beaker of volume capacity at least twice that occupied by the finalstock solution. This is done to allow room for vigorous mixing duringhomogenization. The dye is weighed and added to the water to obtain a 5%(w/w) concentration. The dispersion is then homogenized by arotor-stator homogenizer (Polyscience, model no. X-520) using theprocedure listed in the table below. The procedure is repeated 2-3 timesto ensure sufficient dye dispersion and particle size reduction fordissolution.

Step Duration (seconds) Homogenize at 11,000 rpm* 15 Homogenize at15,000 rpm* 15 Homogenize at 19,000 rpm* 15 Homogenize at 22,000 rpm* 15Homogenize at 26,000 rpm* 15 Stop homogenizer, and use 60 pipette torinse sides of beaker with dispersion *rpm = revolutions per minute

Preparation of Film Coating Formulations

The stock solutions are blended together to achieve the desired solidconcentration of each ingredient in the resulting film coatingformulation. For example, the low-hydroxypropyl cellulose ether stocksolution is weighed into a tared jar. Next, polyethylene glycol (PEG)(in its pure form) is added. Then, the FD&C Yellow No. 5 stock solutionis added. Finally, a sufficient quantity of water is added to thetargeted concentration. The film coating formulation is allowed to mixfor at least 30 minutes using a StedFast Stirrer (model no. SL 600,Fisher Scientific) equipped with a marine propeller-type stirring shaft.

Viscosity Measurement

The viscosity of the film coating formulation is measured using aBrookfield Digital Viscometer (model no. DV-II, Brookfield EngineeringLaboratories, Inc.) equipped with an RV spindle set. Spindles 1 through7 are used as necessary throughout the studies depending upon theviscosity of the film coating formulation. The spindle rotation settingsused are dial readings of 0.5, 1, 2.5, 5, 10, 20, 50 and 100, with 0.5being the slowest rotation speed and 100 the fastest. To prepare theinstrument, the largest spindle necessary is estimated (depending uponvisual observation of the sample viscosity) and attached to theviscometer. The viscometer is then calibrated for that particularspindle. The digital display is programmed to provide the viscosity datain cP units. The dial is set to 0.5, and the spindle motor is turned on.The dial setting is gradually increased until the low indicator light isturned off, indicating that the spindle speed is sufficient to obtain avalid viscosity reading. Viscosity is recorded. Spindle setting isincreased, and viscosity readings are recorded until the digital displayread “EEE”. This indicates that the spindle speed has become too rapidto obtain a valid viscosity reading. The motor to the viscometer isturned off prior to removal of the spindle. Each time a differentspindle is used, the viscometer is calibrated for that particularspindle and the display programmed to provide the viscosity data in cPunits. If possible, one to three spindles are used to test viscosity.

Film Coating Application

Scored, oval placebo tablets (400 mg per tablet) are compressed using0.49″×0.27″ concaved tooling. The tablet formulation is listed in thetable below.

Placebo Tablets   85% Pharmatose ® DCL11, Spray Dried (lactose)-DMVInternational Lot No. 10242933 14.5% Avicel ® PH-102 (microcrystallinecellulose)-FMC BioPolymer Lot No. P205815128  0.5% MagnesiumStearate-Mallinckrodt Lot No. C09465_

Tablets are coated with the film coating formulations using a HI-COATER(model LDCS, Vector Corporation) equipped with a 1.3-L baffled pan. Thespray nozzles are cleaned and calibrated using the “F3: Calibrate Guns”menu. The film coating trial parameters are programmed using the “F1:Manual Process” menu.

Prior to film coating, the tablets are de-dusted by placing them on asieve and spraying compressed air through the tablet bed. Next, a 600-gbatch of tablets is weighed and introduced into the pan, and the exhaustblower and process heat are initiated. The tablets are allowed toequilibrate to the desired temperature for up to 30 min prior toinitiating the coating trial. Exhaust temperature is used as theoperating temperature set point, meaning that the heat is automaticallyadjusted to maintain the exhaust air at a relatively constanttemperature. Once the desired exhaust temperature is attained, the panis operated in continuous fashion, and the film coating formulation isatomized onto the tumbling tablet bed via the nozzle. After the desiredamount of film coating formulation has been introduced onto the tumblingtablet bed, atomization is stopped, and the film-coated tablets aretumbled continuously for 30 minutes to dry. After drying, the pan,process heat and exhaust blower are stopped in that order.

The tablets are weighed before and after film coating to determine thepercent weight gain. The film-coated tablets are visually inspected forbridging, coating of sharp curvatures, edging, and coat smoothness andhomogeneity.

Results

Low-Hydroxypropyl Cellulose Ether Coating Composition

The low-hydroxypropyl cellulose ether coating composition along with theparameters used to coat tablets are listed in the tables below. Thecomposition contains a total of 23.94% solids, low-hydroxypropylcellulose ether 2.66VLV comprised 21% of the 23.94% total solids. Thefact that a 21% concentration of the low-hydroxypropyl cellulose ethercoating composition is achieved is surprising because the viscosityremained sufficiently low to allow for atomization and tablet coating.Typically, METHOCEL concentrations for film coating do not exceed 10%,so the greater than 2-fold increase in cellulose ether concentrationwith the low-hydroxypropyl cellulose ether coating composition issignificant. The desired amount of coating is applied within 28.4 min,and the weight gain is 3.56% (4% target). The coated tablets are ofexcellent quality. The applied coating is smooth and uniform.

Low-hydroxypropyl Cellulose Ether Coating Composition Ingredient Solids% (w/w) Target Qty. (g) Low-hydroxypropyl cellulose 21.00 105.00 (30%stock sol.) ether “F2.66VLV” PEG 400 2.14  3.21 FD&C Yellow No. 5 0.8 3.45 (10% stock sol.) Water — 38.34 Total 23.94 150.00 

Low-hydroxypropyl Cellulose Ether Coating Composition Viscosity(Brookfield Viscosity) Spindle Dial Setting Viscosity (cP) 3 50 1.07 ×10³ 3 100 EEE

Low-hydroxypropyl Cellulose Ether Coating Composition Trial ParametersPan Size 1.3 L Exhaust Temperature Set point 35° C. Inlet Airflow Rate45 cfm Pan Speed 20 rpm Peristaltic Pump Rate 8 rpm Avg. Spray Rate 3.58g/min Nozzle Atomization Pressure 35 psi

Low-hydroxypropyl Cellulose Ether Coating Composition Results CoatingTime 28.4 min Tablet Weight Gain Target 4.00% Actual 3.56% Tablet BatchWeight Start 600.01 g Finish 621.40 g Tablet Appearance No visibleedging on tablets. Tablets are smooth to touch, no speckling with slightshine. Overall aesthetically acceptable looking tablets. Can see smallskin on nozzle,

For purposes of United States patent practice, the contents of anypatent, patent application or publication referenced herein are herebyincorporated by reference in their entirety herein, especially withrespect to the disclosure of structures, synthetic techniques andgeneral knowledge in the art. It should be understood that variouschanges and modifications to the presently preferred embodimentsdescribed herein will be apparent to those skilled in the art. Suchchanges and modifications can be made without departing from the spiritand scope of the present disclosure and without diminishing its intendedadvantages. It is therefore intended that such changes and modificationsbe covered by the appended claims.

1. A composition comprising: an aqueous solution of a very low viscositycellulose ether present in an amount of at least 10% by weight of thecomposition, the very low viscosity cellulose ether having a molecularweight such that a 2% by weight aqueous solution of it at 20° C. has aviscosity from 1.2 mPa·s to less than 2 mPa·s; and a plasticizer.
 2. Thecomposition of claim 1 wherein the cellulose ether is a very low colorcellulose ether. 3.-4. (canceled)
 5. The composition of claim 1comprising a second cellulose ether.
 6. (canceled)
 7. The composition ofclaim 1 wherein the composition has a total solids content from at least10% by weight to about 40% by weight.
 8. The composition of claim 1wherein the viscosity of the composition is from 100 cP to 1000 cP.
 9. Acoated composition comprising: a substrate; and a coating on thesubstrate, the coating comprising a plasticizer and a very low viscositycellulose ether present in an amount of at least 10% by weight of thecoating, the very low viscosity cellulose ether having a molecularweight such that a 2% by weight aqueous solution of it at 20° C. has aviscosity from 1.2 mPa·s to less than 2 mPa·s. 10.-39. (canceled) 40.The composition of claim 1 comprising the very low viscosity celluloseether in an amount of at least 20% by weight of the composition.
 41. Thecomposition of claim 1 wherein the very low viscosity cellulose ether isa methylcellulose, hydroxyethyl cellulose, hydroxypropyl cellulose,hydroxyethylmethyl cellulose, hydroxypropylmethyl cellulose,hydroxybutylmethyl cellulose, ethylhydroxyethyl cellulose, carboxymethylcellulose, or carboxymethyl hydroxyethylcellulose.
 42. The compositionof claim 1 wherein the very low viscosity cellulose ether is ahydroxypropylmethyl cellulose.
 43. The composition of claim 1 whereinthe very low viscosity cellulose ether has an APHA color value of from 1to
 100. 44. The composition of claim 1 wherein the plasticizer isselected from the group consisting of polyethylene glycol, castor oil,dibutyl sebacate, diethyl phthalate, glycerol, polyethylene glycolmethyl ether, triacetin, triethyl citrate, phospholipids, lecithin,propylene glycol and combinations thereof in an amount of from 1 to 10%by weight of the composition.
 45. The composition of claim 1 wherein thecomposition has a total solids content from 20% by weight to about 40%by weight.
 46. A coated composition of claim 9 wherein the substrate isselected from the group consisting of tablets for oral ingestion, foodproducts, pharmaceutical capsules, medicaments, drugs, seeds, animalfeed, granules, beads, powder, encapsulates, troches and fertilizers.47. The coated composition of claim 9 wherein the substrate comprises asurface and an edge, and the coating covers the surface and the edge.48. The coated composition of claim 9 comprising a uniform coating onthe surface and the edge.
 49. The coated composition of claim 9 whereinthe coating is a single layer.
 50. The coated composition of claim 9wherein the very low viscosity cellulose ether is a methylcellulose,hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethylmethylcellulose, hydroxypropylmethyl cellulose, hydroxybutylmethyl cellulose,ethylhydroxyethyl cellulose, carboxymethyl cellulose, or carboxymethylhydroxyethylcellulose.
 51. The coated composition of claim 9 wherein thevery low viscosity cellulose ether is a hydroxypropylmethyl cellulose.52. The coated composition of claim 9 wherein the very low viscositycellulose ether has an APHA color value of from 1 to
 100. 53. The coatedcomposition of claim 9 wherein the plasticizer is selected from thegroup consisting of polyethylene glycol, castor oil, dibutyl sebacate,diethyl phthalate, glycerol, polyethylene glycol methyl ether,triacetin, triethyl citrate, phospholipids, lecithin, propylene glycoland combinations thereof in an amount of from 1 to 10% by weight of thecoating.